Dear Medical Doctors,
Over the past 2-3 months I have smoked marijuana VERY occasionally. I have shared about 5-6 joints with other people, the total effect being as if I had probably smoked between around one or two marijuana joints by myself. I have also in the process of smoking marijuana probably consumed around half a cigarrette's worth of tobacco in adding agents to better burn the joints. I know this amount of tobacco is so negligable, and in a week of walking around in any city's downtown I'd get more than this, but I am still worried and would still like to ask
I am a 16 year old healthy male in a family of non-smokers and non-drinkers and I am on no medications.
Would the amount of substances I have smoked have any permanent damange on my lungs? I have heard the lungs have a natural ability to clean themselves. Can the lungs clean out stains and tars and toxins from smoking? Have my lungs been damaged, and if so, will they ever return to the way they were?
Thank you very much.
On a similar topic, I have a question about using a vaporizer as an alternative to smoking. I know that most of the chemicals found in smoke are there due to combustion, not due to the herb itself of marijuana. Assuming one heated the substance enough to release THC in gaseous form, and inhaled the vapor, could that damage one's lungs?
Thank you very much in advance for reading my question, and I hope you will answer it for me.

It is a little more complicated than this. It is believed that some people have a genetic predisposition to harmful effects of tobacco and other substances. We do not currently have a way to determine this but it explains why some smokers are never affected and other non-smokers get cancer from second-hand smoke, even in negligible amounts.

So from a health standpoint there is no such thing as an insignificant exposure. You have no way of knowing how your body will respond and what permanent effects there may be. You play Russian Roulette when you smoke or inhale in any way, known harmful substances. For your future health and well-being, I would put my efforts in trying to quit this habit before you do any further damage.

It is known that some people do recover well from smoking in the past. Again, it is an individual thing. We do know that quitting has a very positive effect on the future chances of getting lung cancer, emphysema, asthma, etc.

Good luck. I hope you will make wise choices to avoid a future of worry and possible serious consequences.